Next Generation Markers to Accelerate Grape Cultivar Improvement

Molecular DNA markers can be used to tag traits in the genome, providing optimal selection of parents and early selection of elite progeny with multiple desirable traits and/or multiple resistance genes for improved durability. The purpose of this project was to develop a pipeline for applying molecular markers in public grape breeding programs. In this pilot project, two public breeding programs were invited to submit up to 1000 leaf samples each to the Cadle-Davidson lab for DNA extraction, quality control, and processing with markers already discovered and potentially relevant to their breeding programs. Drs. Ramming and Reisch decided to provide populations focused on powdery mildew resistance and seedlessness for validation of known marker-trait associations. We tested three markers linked with seed development inhibitor (SdI) and found that combining the marker data resulted in enhanced selection of seedlings with little or no seed trace. Using stringent selection in three populations, 100{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} of progeny with SdI markers were seedless. These markers would enable breeders, depending on their preferred stringency, to discard up to three-quarters of young seedlings solely based on predictions of seedlessness. This would enable the focused evaluation of more crosses and more elite progeny.